1. Field of the Invention
The present invention relates to a download method, and a user terminal and a delivery server therefor.
2. Related Art
JP-A-H7-30573 proposes a download method for downloading the same data to all slave stations (user terminals). The method first sends a download request including a data identifier from a master station (sender) to slave stations which are directly connected to the master station. Each of the slave stations which have received the download request determines whether to accept or reject the download request based on the data identifier. The master station sends the data corresponding to the data identifier to the slave stations which have accepted the download request. Each of the slave stations which have received the data sends the received data in turn to slave stations which are connected thereto. This process is repeated, so that the same data is downloaded to all the slave stations.
This method downloads the data from the master station to the slave stations which are directly connected thereto via a wide area network (WAN), and sends the data to the rest of the slave stations via a local area network (LAN) in parallel. Therefore the total time required for downloading the same data to all the slave stations is reduced in comparison with a conventional method which downloads the data from a master station directly to all slave stations.
However, according to JP-A-H7-30573, the master station sends the entire data to each of the slave stations directly connected thereto. Therefore a relatively large amount of data is sent via the WAN. That is, it still takes a relatively long time to download the same data to all the slave stations.